dịch bài này hộ mik nhé
----- Nội dung dịch tự động từ ảnh -----
Water pollution is a major global problem which requires ongoing evaluation and
revision of water resource policy at all levels. It has been suggested that water pollution
is the leading worldwide cause of deaths and diseases, and that it accounts for the
deaths of more than 14,000 people daily. An estimated 580 people in India die of water
pollution related illness every day. About 90 percent of the water in the cities of China is
polluted. As of 2007, half a billion Chinese had no access to safe drinking water. In
addition to the acute problems of water pollution in developing countries, developed
countries also continue to struggle with pollution problems. For example, in the most
recent national report on water quality in the United States, 44 percent of assessed
stream miles, 64 percent of assessed lake acres, and 30 percent of assessed bays and
estuarine square miles were classified as polluted. The head of China's national
development agency said in 2007 that one quarter the length of China's seven main
rivers were so poisoned the water harmed the skin.
Water is typically referred to as polluted when it is impaired by anthropogenic
contaminants and either does not support a human use, such as drinking water, or
undergoes a marked shift in its ability to support its constituent biotic communities,
such as fish. Natural phenomena such as volcanoes, algae blooms, storms, and
earthquakes also cause major changes in water quality and the ecological status of
water.